timezone/tzselect.ksh

   1 #!/bin/bash
   2
   3 PKGVERSION='(tzcode) '
   4 TZVERSION=see_Makefile
   5 REPORT_BUGS_TO=tz@iana.org
   6
   7 # Ask the user about the time zone, and output the resulting TZ value to stdout.
   8 # Interact with the user via stderr and stdin.
   9
  10 # Contributed by Paul Eggert.
  11
  12 # Porting notes:
  13 #
  14 # This script requires a Posix-like shell with the extension of a
  15 # 'select' statement.  The 'select' statement was introduced in the
  16 # Korn shell and is available in Bash and other shell implementations.
  17 # If your host lacks both Bash and the Korn shell, you can get their
  18 # source from one of these locations:
  19 #
  20 #       Bash <http://www.gnu.org/software/bash/bash.html>
  21 #       Korn Shell <http://www.kornshell.com/>
  22 #       Public Domain Korn Shell <http://www.cs.mun.ca/~michael/pdksh/>
  23 #
  24 # This script also uses several features of modern awk programs.
  25 # If your host lacks awk, or has an old awk that does not conform to Posix,
  26 # you can use either of the following free programs instead:
  27 #
  28 #       Gawk (GNU awk) <http://www.gnu.org/software/gawk/>
  29 #       mawk <http://invisible-island.net/mawk/>
  30
  31
  32 # Specify default values for environment variables if they are unset.
  33 : ${AWK=awk}
  34 : ${TZDIR=$(pwd)}
  35
  36 # Check for awk Posix compliance.
  37 ($AWK -v x=y 'BEGIN { exit 123 }') </dev/null >/dev/null 2>&1
  38 [ $? = 123 ] || {
  39         echo >&2 "$0: Sorry, your \`$AWK' program is not Posix compatible."
  40         exit 1
  41 }
  42
  43 if [ "$1" = "--help" ]; then
  44     cat <<EOF
  45 Usage: tzselect
  46 Select a time zone interactively.
  47
  48 Report bugs to $REPORT_BUGS_TO.
  49 EOF
  50     exit
  51 elif [ "$1" = "--version" ]; then
  52     cat <<EOF
  53 tzselect $PKGVERSION$TZVERSION
  54 EOF
  55     exit
  56 fi
  57
  58 # Make sure the tables are readable.
  59 TZ_COUNTRY_TABLE=$TZDIR/iso3166.tab
  60 TZ_ZONE_TABLE=$TZDIR/zone.tab
  61 for f in $TZ_COUNTRY_TABLE $TZ_ZONE_TABLE
  62 do
  63         <$f || {
  64                 echo >&2 "$0: time zone files are not set up correctly"
  65                 exit 1
  66         }
  67 done
  68
  69 newline='
  70 '
  71 IFS=$newline
  72
  73
  74 # Work around a bug in bash 1.14.7 and earlier, where $PS3 is sent to stdout.
  75 case $(echo 1 | (select x in x; do break; done) 2>/dev/null) in
  76 ?*) PS3=
  77 esac
  78
  79
  80 # Begin the main loop.  We come back here if the user wants to retry.
  81 while
  82
  83         echo >&2 'Please identify a location' \
  84                 'so that time zone rules can be set correctly.'
  85
  86         continent=
  87         country=
  88         region=
  89
  90
  91         # Ask the user for continent or ocean.
  92
  93         echo >&2 'Please select a continent or ocean.'
  94
  95         select continent in \
  96             Africa \
  97             Americas \
  98             Antarctica \
  99             'Arctic Ocean' \
 100             Asia \
 101             'Atlantic Ocean' \
 102             Australia \
 103             Europe \
 104             'Indian Ocean' \
 105             'Pacific Ocean' \
 106             'none - I want to specify the time zone using the Posix TZ format.'
 107         do
 108             case $continent in
 109             '')
 110                 echo >&2 'Please enter a number in range.';;
 111             ?*)
 112                 case $continent in
 113                 Americas) continent=America;;
 114                 *' '*) continent=$(expr "$continent" : '\([^ ]*\)')
 115                 esac
 116                 break
 117             esac
 118         done
 119         case $continent in
 120         '')
 121                 exit 1;;
 122         none)
 123                 # Ask the user for a Posix TZ string.  Check that it conforms.
 124                 while
 125                         echo >&2 'Please enter the desired value' \
 126                                 'of the TZ environment variable.'
 127                         echo >&2 'For example, GST-10 is a zone named GST' \
 128                                 'that is 10 hours ahead (east) of UTC.'
 129                         read TZ
 130                         $AWK -v TZ="$TZ" 'BEGIN {
 131                                 tzname = "[^-+,0-9][^-+,0-9][^-+,0-9]+"
 132                                 time = "[0-2]?[0-9](:[0-5][0-9](:[0-5][0-9])?)?"
 133                                 offset = "[-+]?" time
 134                                 date = "(J?[0-9]+|M[0-9]+\.[0-9]+\.[0-9]+)"
 135                                 datetime = "," date "(/" time ")?"
 136                                 tzpattern = "^(:.*|" tzname offset "(" tzname \
 137                                   "(" offset ")?(" datetime datetime ")?)?)$"
 138                                 if (TZ ~ tzpattern) exit 1
 139                                 exit 0
 140                         }'
 141                 do
 142                         echo >&2 "\`$TZ' is not a conforming" \
 143                                 'Posix time zone string.'
 144                 done
 145                 TZ_for_date=$TZ;;
 146         *)
 147                 # Get list of names of countries in the continent or ocean.
 148                 countries=$($AWK -F'\t' \
 149                         -v continent="$continent" \
 150                         -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 151                 '
 152                         /^#/ { next }
 153                         $3 ~ ("^" continent "/") {
 154                                 if (!cc_seen[$1]++) cc_list[++ccs] = $1
 155                         }
 156                         END {
 157                                 while (getline <TZ_COUNTRY_TABLE) {
 158                                         if ($0 !~ /^#/) cc_name[$1] = $2
 159                                 }
 160                                 for (i = 1; i <= ccs; i++) {
 161                                         country = cc_list[i]
 162                                         if (cc_name[country]) {
 163                                           country = cc_name[country]
 164                                         }
 165                                         print country
 166                                 }
 167                         }
 168                 ' <$TZ_ZONE_TABLE | sort -f)
 169
 170
 171                 # If there's more than one country, ask the user which one.
 172                 case $countries in
 173                 *"$newline"*)
 174                         echo >&2 'Please select a country.'
 175                         select country in $countries
 176                         do
 177                             case $country in
 178                             '') echo >&2 'Please enter a number in range.';;
 179                             ?*) break
 180                             esac
 181                         done
 182
 183                         case $country in
 184                         '') exit 1
 185                         esac;;
 186                 *)
 187                         country=$countries
 188                 esac
 189
 190
 191                 # Get list of names of time zone rule regions in the country.
 192                 regions=$($AWK -F'\t' \
 193                         -v country="$country" \
 194                         -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 195                 '
 196                         BEGIN {
 197                                 cc = country
 198                                 while (getline <TZ_COUNTRY_TABLE) {
 199                                         if ($0 !~ /^#/  &&  country == $2) {
 200                                                 cc = $1
 201                                                 break
 202                                         }
 203                                 }
 204                         }
 205                         $1 == cc { print $4 }
 206                 ' <$TZ_ZONE_TABLE)
 207
 208
 209                 # If there's more than one region, ask the user which one.
 210                 case $regions in
 211                 *"$newline"*)
 212                         echo >&2 'Please select one of the following' \
 213                                 'time zone regions.'
 214                         select region in $regions
 215                         do
 216                                 case $region in
 217                                 '') echo >&2 'Please enter a number in range.';;
 218                                 ?*) break
 219                                 esac
 220                         done
 221                         case $region in
 222                         '') exit 1
 223                         esac;;
 224                 *)
 225                         region=$regions
 226                 esac
 227
 228                 # Determine TZ from country and region.
 229                 TZ=$($AWK -F'\t' \
 230                         -v country="$country" \
 231                         -v region="$region" \
 232                         -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 233                 '
 234                         BEGIN {
 235                                 cc = country
 236                                 while (getline <TZ_COUNTRY_TABLE) {
 237                                         if ($0 !~ /^#/  &&  country == $2) {
 238                                                 cc = $1
 239                                                 break
 240                                         }
 241                                 }
 242                         }
 243                         $1 == cc && $4 == region { print $3 }
 244                 ' <$TZ_ZONE_TABLE)
 245
 246                 # Make sure the corresponding zoneinfo file exists.
 247                 TZ_for_date=$TZDIR/$TZ
 248                 <$TZ_for_date || {
 249                         echo >&2 "$0: time zone files are not set up correctly"
 250                         exit 1
 251                 }
 252         esac
 253
 254
 255         # Use the proposed TZ to output the current date relative to UTC.
 256         # Loop until they agree in seconds.
 257         # Give up after 8 unsuccessful tries.
 258
 259         extra_info=
 260         for i in 1 2 3 4 5 6 7 8
 261         do
 262                 TZdate=$(LANG=C TZ="$TZ_for_date" date)
 263                 UTdate=$(LANG=C TZ=UTC0 date)
 264                 TZsec=$(expr "$TZdate" : '.*:\([0-5][0-9]\)')
 265                 UTsec=$(expr "$UTdate" : '.*:\([0-5][0-9]\)')
 266                 case $TZsec in
 267                 $UTsec)
 268                         extra_info="
 269 Local time is now:      $TZdate.
 270 Universal Time is now:  $UTdate."
 271                         break
 272                 esac
 273         done
 274
 275
 276         # Output TZ info and ask the user to confirm.
 277
 278         echo >&2 ""
 279         echo >&2 "The following information has been given:"
 280         echo >&2 ""
 281         case $country+$region in
 282         ?*+?*)  echo >&2 "      $country$newline        $region";;
 283         ?*+)    echo >&2 "      $country";;
 284         +)      echo >&2 "      TZ='$TZ'"
 285         esac
 286         echo >&2 ""
 287         echo >&2 "Therefore TZ='$TZ' will be used.$extra_info"
 288         echo >&2 "Is the above information OK?"
 289
 290         ok=
 291         select ok in Yes No
 292         do
 293             case $ok in
 294             '') echo >&2 'Please enter 1 for Yes, or 2 for No.';;
 295             ?*) break
 296             esac
 297         done
 298         case $ok in
 299         '') exit 1;;
 300         Yes) break
 301         esac
 302 do :
 303 done
 304
 305 case $SHELL in
 306 *csh) file=.login line="setenv TZ '$TZ'";;
 307 *) file=.profile line="TZ='$TZ'; export TZ"
 308 esac
 309
 310 echo >&2 "
 311 You can make this change permanent for yourself by appending the line
 312         $line
 313 to the file '$file' in your home directory; then log out and log in again.
 314
 315 Here is that TZ value again, this time on standard output so that you
 316 can use the $0 command in shell scripts:"
 317
 318 echo "$TZ"